Known in the art is a process for obtaining phosphorus from a phosphorus slime (cf. U.S. Pat. No. 3,004,834 Cl. 23-293).
The process is effected by bubbling a stream of an overheated steam at a temperature of from 162.degree. to 172.degree. C. under a pressure of from 6 to 8 atm through the phosphorus slime. The overheated steam is fed through steam needles or bubbling rings. A mixture of water vapours and phosphorus is cooled in tubular condensers. Phosphorus in the form of a liquid phase flows into a special collecting vessel. The process duration is 60 to 120 hours. The yield of phosphorus is 99.5% by mass. The process productivity in a single unit is 2.5 t of phosphorus a day.
The process features a low product output, a high power consumption rate (18-20 kg of steam per 7 kg of the resulting phosphorus) and high rates of corrosion of the equipment.
Also known is a process for producing phosphorus from an aqueous suspension of a phosphorus slime which is subjected to the effect of a DC electric field in a two-section electrophoretic electrolyzer (cf. USSR Inventor's Certificate No. 1039982, C 25 B 7/00, 07.06. 1980). Basic requirements of the process are maintaining temperature surpassing the melting point of phosphorus, pH of the medium=2-3, electric field intensity--not below 35V/cm. When these requirements are observed, impurities pass into a cathode chamber, whereas in an anode chamber yellow phosphorus remains. The yield of phosphorus is 99% by mass. The process productivity is 9 g/h.
This process is characterized by the necessity of a continuous control of its parameters (keeping the required pH, electric field intensity, continuous heat removal from the reaction zone) and by a low productivity.
A combination of the above-mentioned disadvantages has resulted in impossibility of implementation of the process on a commercial scale.